This genus is characterized by the slight development of the fasciole, which is not keeled. The columellar area is excavated at its junction with the parietal wall and becomes considerably twisted further down, though this twist occurs more regularly and less abruptly than in the other groups. This specific excavation renders the columella slightly oblique, ultimately providing the shell with an aperture reminiscent of a Verconella (synonym of Penion P. Fischer, 1884)
Perhaps the most significant and definitive distinguishing feature of Austrofusus is the protoconch. It is consistently conic, polygyrate, and sharply pointed, consisting of three or four smooth whorls. These are followed by a half to three-quarter whorl displaying a brephic sculpture of curved, backwardly sloping axial riblets, which are spaced at twice their own width. In contrast, Cominella J. E. Gray, 1850 possesses a paucispiral, globose, and slightly asymmetrical embryo that exhibits very little distinct brephic sculpture.
Evolution
Austrofusus glans is not closely related to other extant New Zealand buccinid whelks, and is instead related to the Northern Hemisphere genus Colus.
↑Finlay, H.J. (1926). "Finlay". Transactions of the New Zealand Institute. 56: 233. Retrieved 31 March 2026. This article incorporates text from this source, which is in the public domain.
↑Vaux, Felix; Hills, Simon F.K.; Marshall, Bruce A.; Trewick, Steven A.; Morgan-Richards, Mary (2017). "A phylogeny of Southern Hemisphere whelks (Gastropoda: Buccinulidae) and concordance with the fossil record". Molecular Phylogenetics and Evolution. 114 (2017): 367–381. doi:10.1016/j.ympev.2017.06.018. PMID28669812.